VPC peering and AWS Transit Gateway are two AWS services or features that give users the ability to create a network connection between two VPCs. VPC peering is a networking connection between two VPCs that enables you to route traffic between them privately. You can create a VPC peering connection between your own VPCs, with a VPC in another AWS account, or with a VPC in a different AWS Region. Traffic between peered VPCs never traverses the public internet. VPC peering does not support transitive peering relationships, which means that if VPC A is peered with VPC B, and VPC B is peered with VPC C, then VPC A and VPC C are not automatically peered789. AWS Transit Gateway is a networking service that acts as a regional router for your VPCs and on-premises networks. You can attach up to 5,000 VPCs and VPN connections to a single transit gateway and route traffic between them. AWS Transit Gateway simplifies the management and scalability of your network architecture, as you only need to create and manage a single connection from the central transit gateway to each connected network. AWS Transit Gateway supports transitive routing, which means that any network thatis attached to the transit gateway can communicate with any other network that is attached to the same transit gateway . References: 7: VPC peering - Amazon Virtual Private Cloud, 8: Connect VPCs using VPC peering - Amazon Virtual Private Cloud, 9: Amazon VPC-to-Amazon VPC connectivity options - Amazon Virtual Private Cloud, : [AWS Transit Gateway - Amazon Web Services], : [Connect VPCs using AWS Transit Gateway - Amazon Virtual Private Cloud], : [AWS Transit Gateway: Simplify Your Network Architecture]